Wireless technologies continue to evolve, increasingly providing tremendous ease and efficiency of once laborious business and personal tasks. Long-range cellular and other wireless networks have made possible today's mobile society, allowing mobile voice communication, messaging, multimedia communications, e-mail, Internet access, and access to a wide range of wireless applications and services. Short-range wireless technologies have also made significant strides in today's society, both in the personal and business arenas. One such short-range wireless technology involves Radio Frequency Identification (RFID) technology.
Generally, RFID technology utilizes electromagnetic or electrostatic coupling in the radio frequency (RF) portion of the electromagnetic spectrum. RFID readers include at least an antenna and transceiver, where an RF signal may be transmitted from the RFID reader. The RF signal activates transponders or “tags” when touched to, or comes within a predetermined range of, the tags. When a tag has been activated, it transmits information back to the RFID reader. More particularly, in the case of a passive tag (i.e., having no local power source), the tag may be energized by a time-varying electromagnetic RF wave generated by the RFID reader. When the RF field passes through the antenna coil associated with the tag, a voltage is generated across the coil. This voltage is ultimately used to power the tag, and make possible the tag's return transmission of information to the reader, sometimes referred to as backscattering.
RFID tags may be beneficially used in any number of situations. For example, a business may associate tags with their products to facilitate tracking, sorting, or otherwise monitoring products through manufacturing, logistics, inventory, or other pre-sale supply chain stages. RFID readers can be used at various stages of the supply chain to perform such functions. Because these types of supply chain functions generally involve volumes of products moving from place to place, it is generally the most advantageous to employ readers and tags that can communicate at relatively long distances, at least in the RFID context. More particularly, passive tags are often used in such situations due to their relatively low cost versus active tags. While passive tags are limited in their ability to reflect or retransmit (i.e., backscatter) information in response to receiving a reader signal, at some frequencies these distances can be stretched up to a number of meters, which is suitable for certain stages of the supply chain. The distance at which RF communication can be achieved is dependent on a number of factors, such as antenna coil dimensions, emitted reader power, the tag's quality factor, and the frequency of the emitted signal. For example, 900/2400 MHz frequencies are suitable for longer reader-tag distances, and can be on the order of meters.
While longer read distances may be beneficial at some times, they may in other instances be undesirable. For example, the same products being tracked, sorted, and otherwise monitored during pre-sale manufacturing and logistics will likely end up on the shelves of wholesale or retail stores. Relevant product information then becomes less reliant on the characteristics of volumes of product, and more reliant on the product itself. For example, a consumer is likely interested in information relating to an individual product itself, such as the product description, warranty information, cost per unit, and the like.
However, current tag technology is single mode tag technology, in that each tag is configured for a particular read distance. Due to the cost and efficiency benefits of using RFID technology during manufacturing, logistics, and other phases prior to the point of sale, tag technology is driven by these pre-sale business benefits. This results in product tags being forever capable of long read distances. This, however, may be undesirable to the consumer. For example, active long read distances during consumer ownership/use allows the product to essentially be tracked by any RFID reader within the configured range of the product tag, which can be a violation of the consumer's privacy. On the other hand, not having a tag associated with the product eliminates the opportunity for consumers to obtain the benefit of receiving product information while making purchasing decisions and during the useful life of the product. The inability for consumers to take advantage of RFID technology and the associated product information is particularly wasteful in today's society, where RFID readers may be provided in mobile terminals such as mobile phones, Personal Digital Assistants (PDAs), or other mobile devices that the consumers have with them at virtually all times.
Accordingly, there is a need for a manner in which tag information can be accessible to all potential users coming into proximity of items equipped with such tags. The present invention fulfills these and other needs, and offers other advantages over the prior art.